In a heating cartridge of this type (DE 203 08 941 U1), the metal sheathing is provided at one end with a flange, which is directed all round radially outwardly and which is directly embedded in the holder consisting of an injection-molded plastic part and is preferably fitted together with same during the shaping thereof, i.e., during the injection molding operation, to form one assembly unit. The electrical connecting lines are also embedded in the body of the holder and connected in the process to the plug contacts of a plug extending at right angles to the axis of the heating cartridge.
Aside from the fact that the extrusion coating of the flange leads to a larger outside diameter of the holder in this area, it cannot be avoided that a part of the metal sheathing must be extrusion coated as well. This means that the holder requires much space in the area of the end section of the metal sheathing, which space is not available in some applications.
A tubular heating element with a metal sheathing, in which the open end of the metal sheathing is closed by a closing plug consisting of an insulating material, is known from DE 31 17 069 C2. A winding support made of a ceramic material, which is provided with the heating coil and is surrounded by granular insulating material in the metal sheathing, has two axial holes, in which contact pins, which are in contact with the lead-out wires, are accommodated. These contact pins pass through two holes of the closing plug such that the ends of the contact pins close flush with the outer front surface of the closing plug. The blank ends of connecting lines are introduced for contacting into front-side axial holes, which are radially offset by about half the diameter of the contact pins in relation to the contact pins. The contacting fastening of these connecting lines is brought about by radial pressing of the metal sheathing in the area of the closing plug. The end of the metal sheathing, which is tapered by pressing, may be provided with an additional sleeve, optionally with an additional closing piece. However, a coupling element with pluggable contact elements is not provided for in this tubular heating element.